1. Field of the Invention
The present invention relates to a microdissection apparatus and method for microdissecting a biological sample.
2. Description of the Related Art
In recent years, in a field of research of, e.g., genes, a technique to take out only a target cell from a biological sample section is very important to perform a DNA analysis or the like about a specific cell of the biological sample section.
As an apparatus used to cut a necessary cell from a biological sample section under a microscope, a microdissection apparatus adopting a method to collect a necessary area in a sample such as described below has been conventionally proposed.
U.S. Pat. No. 5,998,129 discloses a method by which a sample is fixed on a sample fixing base (slide glass) having a film attached thereto, a necessary area is cut with the film by tracing a contour of the necessary area on the sample with a focused beam of UV laser light transmitted through an objective lens while moving the sample by an electric stage, the cut area is then irradiated with a defocused beam of UV laser light and flipped, the cut sample area is attached to a sample collection adhesive cap arranged above the sample, and it is then collected.
U.S. Pat. No. 6,215,550B1 discloses a method by which a sample collection adhesive cap having an adhesive film, which bonds only an area irradiated with IR laser light, is mounted on a sample, a necessary area on the sample is irradiated with the IR laser light, and the necessary area is collected by bonding only the necessary area on the sample to the adhesive film surface.
A specification of U.S. Patent Application Publication No. 2002/0048747A1 discloses a method by which a sample is fixed on a sample fixing base (slide glass) having a film attached thereto, a sample fixing surface of the sample fixing base is faced downwards, a necessary area on the sample is cut with the film by tracing a contour of the necessary area with UV laser light transmitted through an objective lens from an upper part of the sample fixing base, and the cut sample area is collected by dropping it into a sample collection tube arranged below the sample.
These methods are constituted by a technique to cut a necessary area of a sample under a microscope and a technique to collect the cut area.
Further, in these methods, to trace a contour of a necessary area on a sample with laser light or scan a beam of laser light on an entire necessary area of a sample, there has been put into practical use an apparatus that uses, e.g., an electric XY stage with step motors for moving a sample side with respect to a fixed beam of laser light, or an apparatus that uses, e.g., a laser light beam scanning mechanism with galvano mirrors for scanning a beam of laser light with respect to a fixed sample.
As disclosed in these cited references, in apparatuses adopting the method to trace a contour of a necessary area on a sample with laser light or a method to irradiate an entire necessary area with laser light, since the laser light is applied to the sample while changing a relative position between the beam of laser light and the sample, i.e., since the stage side or the laser light side must be moved, an operation to trace the contour of the necessary area with the laser light requires a considerable time when many necessary areas are scattered on the sample.
Furthermore, when cutting a necessary area by irradiating it with laser light to trace a contour of the necessary area on a sample, the sample tends to be deformed in the middle of dissection resulting from a pressure generated by evaporation of the sample itself or a stress at an uncut part, it is hard to correctly cut the necessary area if the sample is particularly a deformable biological sample. Therefore, when the necessary area is small, not only the necessary area cannot be correctly collected, but also a large amount of impurities may be sometimes mixed, and there occurs a problem that the accuracy of the subsequent analysis of the sample is greatly affected.